go to brambleclan and talk to the redish cat named nutshade. He will tell u to get plumclaw off patrol if ur in fireclan or (i dont remeber their name) off patrol if ur in sunclan. So u talk to ur leader and ask them to go on patrol. Then u go back to Nutshade and he tells u to talk to juniperpaw. talk to him and then go back to nutshade. he will tell u to go to the dead land when the moon is black. Go there and you will see a ghost. talk to them and you will get the acheivement.